This invention relates generally to hopper tees used in bulk material handling, and more specifically pertains to a split collar that fits upon a hopper flange and that pivotally mounts a hinge mutually offset from a cam. A unique aspect of this invention is the hinge and cam bolt mechanism offset upon a common diagonal that allows opening of the assembly for receiving a valve body without disengaging the cam bolt. The invention is especially useful for installing and removing valve bodies where ground clearance is limited.
Hoppers, or tank trailers, regularly transport bulk commodities such as industrial and food products. When the hopper, or tank trailer, reaches its destination, the bulk commodity is unloaded, typically by a power take off driven truck mounted blower or a pneumatic system of a plant or factory. The bulk commodity generally unloads from the hopper and into a pipeline. To complete the unloading, hopper tees are mounted to the discharge outlet of the hoppers, or bins, and include a valve body collocating below the discharge outlet that regulates the amount of product discharged into the hopper tee. The hopper tee conventionally has a vertical section of constant dimension and shape and a horizontal section also of constant dimension and shape forming the inverted T shape configuration. To transfer the bulk commodity, the material is moved out of the hopper, or bin, by gravity flow or air pressure vibration through the valve body and into the vertical section of the hopper tee. The clean discharge pipe is connected to the horizontal section of the tee. Pneumatic conveyance of the bulk material through the pipe occurs by establishing a pressure differential in the pipe.
The prior art hopper tees have a complete, one piece assembly that includes a vertical section, connecting to a hopper, and a horizontal section, connecting to a discharge pipe. The prior art hopper tee design fits below the bottom of the bins of pneumatic tank trailers. Typically, the valve of a bin bolts to the flange of the hopper tee. Installation and removal of a valve typically requires pivoting the hopper tee completely away from the footprint of the valve. Prior art hopper tees generally pivot about an axis parallel to the horizontal section but spaced away from the central longitudinal axis of the hopper tee. In opening a prior art hopper tee, the hopper tee swings downwardly and through nearly a right angle so that the valve body can be installed or removed. Swinging of the hopper tee rotates the tee so that a significant portion of the ground clearance below the hopper becomes occupied by the hopper tee, generally for most of the overall height of the vertical section.
Although prior art hopper tees function well for their intended purposes, some hopper tees lack proper ground clearance for long trailers. Ground clearance has afflicted the tank trailer trucking industry for years. For example, as the hopper tee mounts the tank, ground clearance problems arise when a long trailer, such as a tank trailer, crosses railroad tracks or other uneven surfaces. The longer the trailer, the easier a hopper tee becomes stuck upon a railroad rail, berm, or other short height surface condition. A stuck trailer delays delivery of product to its destination, risks delay penalties to the trucking company, and increases recovery and repair costs of the tank trailers. When a valve jams or requires a size substitution, the clearance between the hopper tee and the ground, rail, hatch, or intake below may be insufficient to fully open the hopper tee from the flange of the hopper. In that situation, the hopper requires movement to a location of suitable ground clearance for valve repairs. However, such movement delays unloading of product and adds to operating costs for a tank trailer trucking company.
The Department of Transportation (DOT) and state highway departments have established heights, widths and lengths the tank trailers must meet. When the hauler transports light density products, such as plastic pellets, the hauler requires a larger cubic foot capacity, or volume, to haul a maximum payload and make hauling such products economically feasible. To increase the cubic foot capacity and remain within DOT height, width and length standards, the prior art and industry have dropped the bottom of the hopper. However, the bottom of the hopper requires angled walls (due to the angle of repose of the bulk material) that funnel down to the hopper tee to allow for emptying of bulk granular material. For most dry bulk products the angle of repose is approximately 45 degrees to the horizontal to obtain the maximum tank volume, in cubic feet, while remaining within the mandated dimensions.